A charged particle beam irradiation device has been known as a device for analysis or observation of a sample with high resolution. For example, in JP 2011-54426 A, an electron beam irradiation device that includes an electron gun, an inlet beam deflector, a converging lens system having two-tiered condenser lenses, an outlet beam deflector, an objective aperture plate, a scanning coil and an objective lens is described.
In the electron beam irradiation device, an electron beam emitted from the electron gun passes through the converging lens system to be converged. Then, the electron beam passes through the objective aperture plate, so that a beam diameter is restricted. Thereafter, the electron beam passes through scanning coils and is scanned in a plane, and the diameter of the electron beam is reduced to a small diameter when the electron beam passes through the objective lens. Then, a sample is irradiated with the electron beam. Secondary electrons, characteristic X-rays or the like are released from the sample irradiated with the electron beam and detected, whereby the sample is observed or analyzed.
The inlet beam deflector is used to align an axis of the electron beam such that the electron beam passes through the center of each condenser lens of the converging lens system. The outlet beam deflector is used to align the axis of the electron beam such that the electron beam passes through the center of the objective lens.